Hook mechanism for lock-stitch sewing machines



Feb. 19, 1924.. 1 1,484,151

.. w. N. PARKES HOOK MECHANISM FOR LOCK 5111011 snwme MACHINES Original Filed July so. 1920 z sheets sheet 1 1N VENTOR fim m Feb. 19, 192

W. N. PARKE? noox MECHANISM FOR LOCK STITCH SEWING MACHINES Originl Filed July so. 1920 2 Sheets-Sheet 2 Pat ented li'ebil9, 1924. I,

1' UNITED STATES WILLIAM N. raaxns, or BROOKLYN, NEW YORK.

HOOK MECHANISM FOR LOCK-STITCH SEWING MACHINES.

Application filed July 30, 1920, Serial Ho. 400,237. Renewed January 8,1924.

Tb all whom it may concern: 7

Be it known that I, WILLIAM N. PARKES, a citizen. of the United States, residing in the borough of Brooklyn, in the county of Kings and State of New York, have invented new and usefulImprovements in a Hook- Mechanism for Lock-Stitch Sewing Machines, of which the following is a specification.

This invention relates to rotary hook lock stitch sewing machines, and its object is to provide an improved hook mechanism for this class of machines.

The invention consists of parts and combination of parts, constructed and incorporated in a sewing machine, as herein illustrated and described, and specifically set forth in the claims.

The parts and combination of parts referred to comprise a primary hook base to which is secured a primary hook; a bobbin case which is provided with a tension device; an auxiliary hook which is preferably secured to the bobbin case; a needle plate adapted for use with the primary hook, and a bobbin case stop which is preferably located separately from the needle plate.

Referring to the main advantages flowing from the invention, it is noted that a more positive, and freer handling of the loop of needle thread is secured, and that this brings about a more favorable condition for speed, and also a condition whereby a given size loop may be passed around a bobbin case constructed to carry a very large supplyof thread.

The bobbin case has an unobstructed open end' for the insertion and removal of the bobbin; the case is self threading while in position in the machine, and the bobbin thread in its passage to the work performs thefunction of guarding the bobbin from rising above the top of the case.

Among the other special features to be noted is, the special adaptation of the invention for use in high speed single needle hemstitch machine. In this connection it is pointed out that in Figures 10 and 19 of the drawings is illustrated a part of the bed of the well known high speed Singer hemstitch machine, with applicants improved hook. mechanism incorporated in it; and it is noted for record here that when this application was filed a complete full size Singer machine of the kind mentioned was chine.

such as it is thought necessary for an understanding of thesaid hook mechanism.

Another feature of the in'ventioito be observed is its construction so the hook, its base, and the bobbin case with its auxiliary hook attached thereto, may all be assembled as a separate unit, and then, by a single screw, this unit may be secured in the ma- In U. S. Patents Nos. 730,692 and 875,623 issued toapplicant June 9, 1903, and December 31', 1907, respectively, is illustrated and described a vertical hook lock stitch forming mechanism. These previous inventions consist mainly of means com-. prising a primary hook in the wall of which is formed a vertical channel that extends substantially from the point of the beak of the hook to its heel, and of a bobbin case having an auxiliary hook secured to it in 1 such a way that the beak of the said auxiliary hook is located in the channel. The base of the said auxiliary hook is constructed in the form of a disc, and this disc part is secured to the bottom of the case, and extends outside the periphery of the same a sufficient extent to engage the edge of the inner wall of the channel of the primary hook and thereby retain the bobbin case in its bearing.

In the present invention applicant also provides a primary hook and an auxiliary hook, but, here these elements are constructed differently. For example, no vertical channel or way is formed in the primary hook, and the auxiliary hook does not perform the function or any part of the function of retaining the bobbin case in its bearing; the base for the primary hook is provided with an upwardly extending cylindrical portion on the periphery of which the primary hook ismounted, and the upper edgeof this cylindrical portion serves as a part of the bearing for the bobbin case and also serves to retain the case in its said bearing.

It will be observed that in the present invention the base of the auxiliary hook is secured in a groove which is formed in the bottom of the bobbin case, that the said base is flush with the bottom of the case, and does not absorb any of the loop as it is cast about the case. It will also; be observed that the present auxiliary hook is provided with neck and beak portions, that the neck portion extends laterally and upwardly from the periphery of the bottom of the bobbin case to a point near the vertical wall of a shallow internal horizontal channel or groove formed in the wall of the primary hook base, and that from this point the said beak portion commences, and extends up wardly, and diagonally in a direction opthe bobbin in t e bobbin case, il ustrating how the bobbin thread as it passes to the work is guided across the top of the case just above the bobbin, and Fig. 3 is a sectional view on lines 3-3 of Fig. 2.

Fig. 4': is a detached top plan view of the bobbin case, and Fig. 5 is a bottom plan view illustrating the location of the auxiliary hook and how it is secured to the case.

Fig. 6 is a rear view of'Fig. 1, and Fig. 7 is a detached view of the bobbin case looking in the direction of the arrow (1 Fig. 4. Fig. 8 is a view of the case looking in the direction of the arrow 6, Fig. 4:, with the tension spring removed.

Fig. 9 is a perspective view of the parts of the hook unit illustrating, in addition to construction, the order in which the parts of this unit go together. i

Fig. 10 is a top plan view of the outer end of the bed of the high speed Singer hemstitch machine before referred to with applicants hook mechanism incorporated therein, and with the hook covering-slides open to expose parts, and to illustrate the relative location of the improved hook mechanism to the feed dog and needle plate of the machine.

Fig. 11 is a detached top plan view of a modified form of needle plate with the feed dog of the machine shown in its operating position, and Fig. 12 is an edge view, with the feed dog omitted, of Fig. 11 looking from right to left, and Fig. 13 is a bottoiii plan view of said needle plate.

Fig. 14 is a sectional View on lines 14-14 I Fig. 11, looking in the direction of the arrow, and Fig.15 is a perspective view of a broken' away part of the modified needle wearer plate illustrating the construction of the bobbin case finger stop lugs and the relative location of these lugs to the needle slot of the needle plate. v

Fig. 16 is a detached top plan view of the regular referred needle plate, and of the outer en of the bobbin case stop arm, 1]- lustratin the construction and relative location 0 these parts, and Fig. 17 is a side view, looking from right to left of Fig. 16.

Fig. 18 is a perspective view of the bobbin case end of the preferred bobbin case stop arm illustrating details of construction of said end, and Fig. 19 is a top plan view of a part of the hook end of the bed of the machine, with parts omitted to disclose the engagement between the end of the bobbin case stop arm and the bobbin case stop finger.

In the drawings (Fig. 9), 1 is a hook base which is provided with the usually constructed downwardly extending'stem 2, the free end 3 of which stem is flattened in a usual manner, to adapt it to be engaged by the usual hook driving mechanism of the high speed Singer vertical hook hemstitch machine in which the invention has been incorporated as before stated. On the hook base is formed an upwardly extending cylindrical portion 4 in which is formed a thread pocket clearance opening 5, over which a hook beak part 6, and a hook tail part 7 project. An integral shallow groove 8 (Figs. 3 and 9) is formed in the wall of the cylindrical portion 4. of the hook base,

and, internal flanges 9 and 10 are the upper.

of the same diameter as the wall of the cylindrical portion 4 of the hook base. The body 16 of the case extends downwardly from the base of the flange 15 to the bottom of the case. Through the vertical wall of said-body are. formed holes 17, and through. the bottom 18 of the case are formed holes 19 (Fig. 5). In the flange 15 is formed a thread pocket 20; the part 21 of this pocket is the loop stop part, and

22 is the loop discharge part.

In portion 23,-of the flange 15 of the case, are formed vertical slots 24, as .best

shown in Figs. 4 and 5, and the upper part of said portion is provided with a thread cast ofl' incline 25. The said portion 23, and the incline formed on it, extend from the loop stop part 21 of the caseto a point indicated by the reference character 26 (Fig. 4). The case is provided with a stop finger 27 which is flush with the upper edge of the case, and which projects horizontally over the loop discharge end of the pocket 20. In connection with this stop finger, it will be observed that the loop discharge part 22 of the pocket extends slightly to the right, horizontally, of the stop finger as best shown in Fig. 4. p

It will also be observed that the stop edge or face 28 of the stop finger 27, is in line centrally with the axis of rotation of the hook mechanism. The bobbin case, from the stop finger 27 to the reference character 29 (Fig. 8), above the flange 15, is provided with a bobbin thread tension wall.

30, and in the periphery of this wall is formed slots 31, and '32, which terminate into thread pockets .33 and 34 respectively.

' The slot 32 enters the lower part of the thread pocket 34, and at the point where it enters this pocket a downwardly projecting guard point 35 is formed. A tension spring 36 (Fig. 4) is secured, by means of attaching screw 37 and tension regulating screw '38, to the said tension wall 30.

Reference character 39 (Fig. 2) represents a depression formed in the upper edge of the wall of the bobbin case to permit of the removal, by the finger or any suitable means, of the bobbin from the case. The cup part of the case is provided with a bobbin post 40 (Fig. 3), through which a hole 41 is formed, and on this post is lo-" cated a bobbin 42, which is provided with thread 43. In the incline 25 of the bobbin case is formed a slot 44 (Figs. 4 and 7), which terminates into the lower part of a thread delivery pocket 45, which pocket is provided with a guard point 46.

It will be observed that the base of the thread pocket 33 is elongated horizontally and that this horizontal part is located below the upper flange of the bobbin, while,

the thread pocket- 34 extends from below the said flange to a point above it. The pocket 45 is located above the upper flange of the bobbin, but, it will be observed. that the guard point 46 of the pocket is located just below the said flange of the bobbin, so that after the bobbin thread is pulled into the pocket the thread will be retained in the pocket by the bobbin.

The reference character 47 (Flg. 9) designates the primary hook ring which is provided with a beak 48, having a loop seizing end or point 49. a throat 50, and a loop cast ofl tail 51. The size of the periphery of the hook ring is reduced, for needle and needle thread clearance, as illustrated at 52. This clearance extends from the part 53 of the hook ring to reference character 53 which is about one-half around the hook 'as best shown in Figs. 9 and 6. The beak of the hook is formed by a slot 54 which runs diagonally in the wall of the hook ring from 55 to the throat 50, and the tail' 51' is'formed by a slot 56 which runs from the end of the tail to its base at 57.

The beginning of the part 53 of the hook ring is slightly in advance of the, point 49 of the beak 48, and is the same distance from the axis of the hook as the said point, so it will be understood that. the part 53 is a needle guard for the point of the beak.

It will be observed that the periphery of.

the beak of the hook-recedes from its point 49 as best shown in Fig. 2. This is for the purpose of providing a clearance between the needle and the beak, just as soon as the point of the beak has passed the needle.

An internal flange'58 is formed at the top of the hook ring, and this flange extends from near the end of the beak around to,

the end of-its tail 51. A-clearancejslot 59 is formed in the wall of the hook near' resents the other end of thiswayr The end 60 of the way is inclined inwardly as indicated'in dotted lines, and the end 61 is inclined outwardly; and these inclines together with the general construction of the parts cause the hook to'reject lint, pieces of thread, or other substance, from the space between the bobbin case and the hook base.

Reference character 62 (Fig. 19) desig- "natesa usual slot which is formed in the upper side of the outer end' of the bed of the Singer hemstitch machine before referred to. In the Singer machine a needle threadloop guard is located in this slot,

but, in place of the Singer guard applicant has.located his improved bobbin case stop arm. which performs the function of restraining the bobbin case from rotation as Well as the function of guarding the loop to assist its formation across the path of the beak of the hook. H Inthe slot 62 is secured, by means of a screw 63, a bobbin case stop arm 64, which is provided at its free end with stop lugs 65 and 66, the construction of which is best shown in Fig. 18. Intermediate these lugs is formed vertically a needle slot 67 of sufficient length horizontally to permit of the lateral movement of the needle, and in the front and rear of this needle slot are formed vertical piercer holes 68 and 69 respectively.

Reference character 70 designates the' lug 66 is constructed the same as the lug 6,5. It will be observed that the inclines formed on the underside of these lugs run upwardly, and on their outer sides inwardly as illustrated'in Fig. 18.

Any suitable needle plate may be used in combination with my improved hook mechanism'. Preferably however, in the present illustration of the invention, a usual,conr

struction of hemstitch machine needle plate of which the bobbin case stop arm 64 may be dispensed with. It will be observed that.

a part, like the end of the said stop arm 64, is constructed on the underside of this modified form of needle plate, and that the lugs of this part are adapted to perform the same functions as the lugs of the stop arm 64. In view of this it is not thought necessany to specify in details this modified needle plate. I

In the bottom of the bobbin case (Fig. 5)- is formed a groove in which is secured-the base 81 of an auxiliary hook which has a 3 neck portion 82, and a beak portion 83. The

beak is inclined at an angle in the opposite direction to the angle of the face of the beak of the primary hook. The end of the beak is designated by reference character 84, and the face by reference character 85 (Fig. The neck portion of thishook is less than a quarter around from the stop finger 27 of the bpbbincase, and this neck inclines upwardlv as best shown in Figs. 5 and 7.

The reference character 86 represents the screw by means of which the hook mechanism may be secured in the before referred to well known high speed vertical hook Singer hemstitch machine. In assembling this hook mechanism the body of the bobbin case 14, with the auxiliary hook attached thereto, is placed in the primary hook base 1,.with the flange 15 .of the case resting on the top of said base. Then the hook ring .47 is placed in position on the base, and secured thereto by means of screws 87, which pass through holes 88, formed through the hook ring, into threaded seats 89, formed in the base.

From this it will be understood that when these hook mechanism elements are secured in position the construction is such that there is a groove between the top of the hook base and the internal flange 58 of the hook ring, and that the flange 15 of the formed for seizure by bobbin thread tension spring may be socured to the case before or after the case is secured in the primary hook. When this hook unit is assembled the beak 85 of the auxiliary hook is located in the shallow groove 8 of the primary hook base, and the end 84 ofisaid beak is close to the underside of the internal flange 9 of the said primary hook base, and substantially in contact with the vertical wall of the groove 8 of the said ase.

The stem 2 of the primary hook is so constructed that it may be secured to the usual hook driving mechanism of the said Singer machine as before stated. This may be done by passing the screw 86 through the hole ll of the-bobbin case, and the hole 12 of the hook base, and then, by ausual screw driver of suitable size securing the said screw into theusual threaded seat formed in the hook driving mechanism of said Singer machine as will .be clearly understood from Figs. 3 and 9.

In connection with the operating of this improved rotary hook mechanism, it will be understood that the point 49 of the beak of the primary hook, in seizing the loop, passes in a path very close to. the'base of the inclines of the underside of the lugs 65 and 66 of the stop arm 64, and that the path of said point is, in a horizontal plane, considerably closer than usual to the, top of the needle plate, or to the underside of the work. The thread pocket 20, it will be observed, is very short and'the flange of the bobbin case in which this pocket is formed is very close to the top of the primary hook ring, and the point 49 of the beak of the primary hook is substantially in line with the top of said ring, as is also the end of the loop delivery tail 51.

The loop of the needle thread, when the primary hook, is located in the needle slots 67 and 78, of the stop arm and needle plate respectively, and

said loop bulges out sufliciently below the base of the said lugs for the end of the beak of the primary hook to enter it. In the operation of the said Singer machine, in which applicant has preferably incorporated his improved hook mechanism as before stated. the part which revolves the hook, as is well known, revolves twice to each reciprocation of the needle, and as applicant has constructed his hook mechanism to be secured to this usual revolving part it willbe understood that applicant has preferably constructed his hook mechanism for use under this usual two to one movement.

In the operation of applicants hook mechanism the beak of the primary hook enters the loop of needlethread and at "thesame time carries it laterally until its inner limb comes into contact with the end 21 of the bobbin case thread pocket 20, and into engagement with the end 84 of the beak of the auxiliary hook. At this point the loop is sufiiciently advanced on the beak of the primary hook to cause it to come into posi tive engagement with the end of the beak ment of the primary hook forces the inner limb of the loop, and through it the loop, rapidly down the beak of the primary hook to its throat 50, and this movement causes the inner limb of the loop to move down the incline 82 of. the neck of the auxiliary hook,

' and to swing rapidly under the bobbin case.

As the end 84 of the auxiliary hook is located in the shallow groove 8 of the primary hook base. just under the internal flange 9, and adjacent the vertical wall of said groove, it will be understood that when the primary hook carries the loop into en gagement with the beak of the auxiliary hook, that the movement thereafter of'the primary hook carriesthe loop positively on to the beak of the auxiliary hook. and down the said beak until it reaches the neck of the auxiliary hook and commences to swing under the bobbin case as stated. And, it will be understood of course. that at the same time the beak of the auxiliary hook is assisting in forcing the loop rapidly down the beak of the primary hook. \Vhen the loop reaches the neck portion of the beak of the auxiliary hook it is deflected downwardly by the underside of said neck portion so that it commences at once to swing under the bobbin case as stated. 7

At practically the same time that the inner limb of the loop commences to swing under the bobbin case the outer limb comes into engagement with the incline 25 of the bobbin case and commences to swing over the top of the case and from this time the two limbs of the loop move substantially parallel with each other to the point of the beginning of loop discharge. Just previous tothe loop being discharged it passes on the cast of? tail 51 of the primary hook, and from here it is drawn to the work.

As the outer limb of the loop passes over the top of the bobbin case, it contacts with the inclines and 71 of the lug 65 o the bobbin case stop arm, and is thereby" caused to pass between the face 28 of the bobbin case stop finger and the said .lug. This, as well as the other features of construction of the invention, adds to the ease and rapidity with which the loop passes around the bobbin case and is discharged for the completion of a stitch.

While the invention is herein illustrated and described adapted for use .in a vertical hook machine of the heinstitch type, in which the needle is moved laterally, it is desired that it be understood that applicant does not wish to be limited in theuse of the invention to this particular kind of machine, as it is obvious that the invention may I claim as new is: of the auxiliary hook, and further move- 1. A stitch forming mechanism comprising a primary hook provided with a beak, a bobbin case provided with an auxiliary hook, means separable from the primary hook for bringing the loop of needle thread into engagement with the auxiliary hook, and the said auxiliary hook so constructed and arranged that it assists in causing the loop of needle thread to move 'rapidly down" so constructed and arranged that it assists in causing the loop of needle thread to move rapidly down the beak of the primary hook, andmeans separate from the auxiliary hook for retaining the bobbin case in the receptacle.

3. A stitch forming mechanism comprising a primary hook having a separable base, the said hook and base constructed so that when they are assembled a groove is formed between them, a bobbin case provided with a peripheral flange which is located in said groove, the body of the bobbin case of such diameter that there is a space between it and the wall of said base, and the bobbin case provided with an auxiliary hook having a beak which operates in said space.

4. A stitch forming mechanism comprising a primary hook provided with a beak,

a bobbin case carried by the said primary hook. said bobbin case provided with an auxiliary hook, the auxiliary hook so constructed and located as to assist in causing the inner limb of the loop of needle thread -tomove rapidly down the beak of the primary hook and under the bobbin case, and the primary hook provided with a tail on which the loop passes as it is being cast from the primary hook.

5. A stitch forming mechanism comprising a primary hook provided with a bobbin case in the bottom of which a groove is formed, a base for the primary hook in which a shallow channel is formed, an auxiliary hook provided with a base and a beak, the base of the auxiliary hook secured in the said groove, and the beak ofthe auxiliary hook located in the said shallow channel. a

' the end of the beak of which is located edge of the case,

under the said internal flange.

7 A stitch forming mechanism comprising a hook which revolves about a vertical axis, a bobbin case carried by said hook, said bobbin case providedwith a stop finger which projects laterally from the upper two suitably located stop lugs, the under side of said lugs inclined upwardly, and the outside of said lugs inclined inwardly, and the end of the said stop finger located between the said lugs.

8. In a sewing machine, a hook base which revolves about a vertical axis, ahook mounted on said base, the said hook provided with I a bobbin case, a horizontally disposedslot formed through the wall of the base of the hook below the bobbin case, and a slot which registers with this slot formed through the body of the hook, and the forward ends of said slots inclined inwardly, and the other or rear ends inclined outwardly.

9. In a sewing machine, a hook base which revolves about a vertical axis, a hook mounted on said base, the said hook provided with a bobbin case, a passage formed through the wall of said base below the bobbin case, a passage formed hook, and a plurality of passages formed through the wall of the bobbin case.

10. In a lock stitch sewing machine, a hook base which revolves about a vertical axis, an upwardly projecting cylindrical bearing formed on said hook base, a hook secured on said bearing, an internal fla e formed at the upper edge of the hook, a be bin caseprovided with a hearing which is located between the upper edge of the said cylindrical bearing and the said internal flange, and a clearance and air circulating way formed through the wall of the cylindrical bearing and the wall of the hook just below the bottom of the bobbin case.

11. In a sewing machine, a horizontally disposed hook, an open end bobbin case proand a way for the delivery of the bobbin thread from the case, and bobbin, and these elements so constructed and located relatively from the bobbin case tension to the said way crosses the open end of the bobbin case.

1-2. In a sewing machine, a horizontally which registers with this passage through the wall of the body of the that the bobbin thread as it is drawn disposed hook, self threading open end bold disposed hook provided with a bobbin case,

the said bobbin case provided with a tension spring, a way .for the bobbin thread formed 13 rough he wall of the bobbin case, the said way so constructed and located'that the bobbin thread passes throulgh the same and then under saidtension spring, a second wayfor the bobbin thread formed through the wall of said bobbin case, the said second way so constructed and located that the upper sideof the bobbin retains the bobbin thread in the way, a third way formed through the wall of the said bobbin case through which the bobbin thread passes to the work, and sald third way so constructed and located that the upper side of the bobbin retains the bobbin thread in said third way.

14. A stitch forming mechanism comprising a horizontally disposed hook and bobbin case, upper edge of said bobbin case, and a' plurality of slots formed, vertically through the outer edge of said thread cast ofi incline.

l 5, A stitch iorming mechanism com ris ing a horizontally disposedhook, a be bin case provided with a peripheral flange which serves as a bearing for the case, the hook provided with a groovein which said flange is located, the bobbin case "provided with a thread cast ofi incline, and av vertical grooves formed in said ange which extend intothe said thread cast ofi incline.-

16. A stitch forming mechanism comprising a horizontally disposed hook, hook base, and. bobbin case, the bobbin lease provided witha centrally located hollow post, a bobbinrnounted on said post, a driving device for said book, a bore formed centrally through said and securesthe hook base the driving device. videdwith a tension forthe bobbin thread In testimony whereof I have signed my a thread cast off incline formed at the did lurality or Z lid post and hook base, and a v 1 single screw which passes through said bore lid name in the presence of two subscribing witnesses. I v

I WILLIAM N. rrinkns. Witnesses:

- HENRY I REMANDEB,

VERA BKANE. 

